Vivek, where are the alias and department? If you're saying that all you have in your Excel spreadsheet is the email address, and the alias and department are in (probably) Outlook, then this isn't really an Excel question: you need to know how to get at the data that's stored in Outlook—or in Active Directory, or LDAP, or wherever it is.
You may be able to expand your VBA/Excel program to fetch that data. But first you have to know where it is now, and how to go get it.
If the alias and department are already in your Excel workbook, then I don't understand the question.